(servlet) downloading a dynamically generated file

I am trying to download a dynamically generated file. It is not a real file I have in the server but an "Apache POI HSSFWorkbook", which can be downloading by the client as an excel sheet (or HorribleSpreadSheetFormat .

I found a lot of aproaches for "real files". How is it with "objects" in cache (like a HSSFWorkbook).

For dynamic files, you could simply write a rountine that writes the dynamic content to the ServletOutputStream when the rountine is invoked. The content can be generated within that rountine as well, no matter a *real* Excel file, or CSV files.

I am using JSF. The download method is in a action-methode which I call from one page. I have to present the "download-Mask" and (after the download or the cancel) return to the same page. So far so good and working well. I can open the downloaded file and it is all ok. BUT My problem is when I try to use another "action method" in that page (after the download) it comes again the "download-Mask" !! even if that has nothing to do with this other "action method".

So: something not closed? I try many other ways with no result...

CODE:

faces-config:

downloadMethod: (as written above I already used other ways like: the write method from HSSFWorkbook, or other dispositions, etc.)